Quantum dots light emitting diodes typically include a light emitting layer having a plurality of cadmium selenide nanocrystals. The cadmium selenide layer is sandwiched between an electron transport layer and a hole transport layer. An electric field is applied to the quantum dots light emitting diode, causing electrons and holes to move into the cadmium selenide layer. In the cadmium selenide layer, the electrons and holes are trapped in the quantum dots and recombine, emitting photons. The emission spectrum of a quantum dots light emitting diode is narrower as compared to conventional organic light emitting diodes.